Various methods have been proposed for removing and recovering acid gases, such as CO2 and H2S, contained in exhaust gases from fossil fuel combustion. One such method brings combustion exhaust gas into contact with an absorbent amine solution such as an alkanolamine aqueous solution to remove and recover acid gas from the combustion exhaust gas.
Such absorbent amine solutions are known to cause corrosion of device materials due to degradation thereof. To address this, Patent Literature 1 describes a method of taking a measure that adds a corrosion inhibitor to an absorbent amine solution and maintains the corrosion inhibitor at a predetermined concentration in the following manner. The method measures the potential difference in the absorbent amine solution that changes with the concentration of the corrosion inhibitor and blows oxygen into the absorbent amine solution when the measured potential difference reaches a predetermined range.
Patent Literature 2 describes a water quality measuring device for obtaining pure water or ultrapure water. The device irradiates organic matter in the water with ultraviolet light to decompose and remove the organic matter and then measures ion concentrations of copper ions and iron ions in the water after the ultraviolet irradiation.